The present invention relates to semiconductor memory devices, and in particular to a semiconductor resistive memory device such as Magnetic or Magnetoresistive Random Access Memory (MRAM), Phase Change memory (PCM), Resistance memory (RRAM) etc.
The nonvolatile MRAM with Spin Transfer Torque (STT) programming has become a topic of great interest. This SST MRAM can be manufactured with the Complementary Metal Oxide Semiconductor (COMS) technology for both the embedded application as well as the stand alone memory device. MRAM combines the desirable attributes of today's memory technologies such as the volatile Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), and the Non-volatile Flash Memory. Some of the key attributes are fast access time, random address selection, low cost, high density, and non-volatility.
However, conventional MRAM suffers from many limitations as will be described below. Therefore, techniques for improving operations of MRAM are highly desired.